The separation of magnetic or magnetizable components such as magnetic particles on the to basis of magnetic forces has been of considerable significance particularly in the field of analytics.
Magnetic particles can, for instance, be used as a binding support for biological materials such as proteins or nucleic acids. In an exemplary typical analytical setting, the magnetic particles are contacted with a liquid sample containing an analyte in a multiwell plate, under conditions that facilitate binding of the analyte to the magnetic particles. The latter can then be subsequently separated from the liquid by means of magnetic forces generated by magnetic pins. U.S. Pat. No. 5,779,907 discloses a device in which such magnetic pins are attached to a base plate, wherein the multiwell plate containing sample and magnetic particles is exposed to a magnetic field generated by the magnetic pins upon physical combination of the pin-bearing base plate with said multiwell plate. In order to invoke a significant magnetic field within the sample fluids, the magnetic pins are moved into close vicinity to the wells by means of being introduced into preadapted recesses in locations of the multiwell plate not containing any samples.
However, the coupling of the above-mentioned plates to each other gives rise to the following problem: When the magnetic pins are being placed into the preadapted recesses within the multiwell plate, tolerances with respect to size and position of the pins and recesses frequently lead to jamming of the system or breakage of the pins as the latter cannot be easily inserted into and/or removed from the recesses.
In the prior art, this problem has been tackled in various manners:                The diameter of the recesses within the multiwell plate has been increased in relation to the diameter of the magnetic pins        The above-mentioned tolerances have been controlled more strictly        Deformability of the multiwell plate has been enhanced.        
The present invention provides an alternative solution displaying several advantages.